...
: memset(UCP &arp.arp_netmask.sa_data[2], UCR 0xff, 0x03); /* 255.255.255.0 */
...
: Jan 15 21:06:15 quark pppd_cache[84]: ARP address added: 204.178.47.17
: Jan 15 21:06:15 quark pppd_cache[84]: (arp_update.c) ioctl(SIOCSARP)
: Invalid argument
: Jan 15 21:06:18 quark pppd_cache[84]: ARP address added: 204.178.47.17
: Jan 15 21:06:18 quark pppd_cache[84]: (arp_update.c) ioctl(SIOCSARP) Invalid argument
You specified netmask 255.255.255.0 and prefix 204.178.47.17,
that is wrong.
Apparently, you wanted to pass either address 204.178.47.0 or
mask 255.255.255.255, did not it?
Alexey Kuznetsov.